/in/foo.cc: In function 'int bfs(int, int)':
/in/foo.cc:40:6: warning: unused variable 'ans' [-Wunused-variable]
  int ans = n * m;
      ^~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:75:3: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
   gets(a[i] + 1);
   ^~~~
In file included from /in/foo.cc:7:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/in/foo.cc:75:16: warning: 'char* gets(char*)' is deprecated [-Wdeprecated-declarations]
   gets(a[i] + 1);
                ^
In file included from /in/foo.cc:7:0:
/usr/include/stdio.h:640:14: note: declared here
 extern char *gets (char *__s) __wur __attribute_deprecated__;
              ^~~~
/tmp/cckS6VZK.o: In function `main':
foo.cc:(.text.startup+0x6b): warning: the `gets' function is dangerous and should not be used.